Snell EII Crossover

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jrc

Snell EII Crossover
« on: 8 Aug 2016, 10:28 pm »
Hi Jeff,
I have some 30yr old Snell EII speakers and would like to get your recommendations for upgrading the crossover and wiring.  Below are some pictures of the crossover and schematic.
Thanks, John












Jeff

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Re: Snell EII Crossover
« Reply #1 on: 9 Aug 2016, 05:17 am »
Hello,

Is there any difference in your XOs from Left to Right other than the trim on R1?  Snell was notorious for measure each driver, and trimming the XO such that the XO was different in the L vs R.  Do you have any particular sonic goals?  Budget?

While it may not look like much, that wire might be a reasonably good litz.  If you have one, take a small/powerful magnet to the back of the binging posts, and the tag boards.  Are they magnetic?  You might consider sending both XOs to me for a free evaluation.  I like to measure every component in Snells.  Here is a couple of pics of one of my meticulous builds (A/III).








jrc

Re: Snell EII Crossover
« Reply #2 on: 13 Aug 2016, 08:01 pm »
Hi Jeff,
Thanks for the reply. Both of the crossovers are the same. Originally, one of the crossovers did not have the .47 Relcap. A tweeter was replaced and the crossover components sent with new tweeter included the Relcap.
The wire is Livewire by Audioquest. When I pulled the woofers, which are in need of refoam, I noticed the wire looked like it had oxidized and might need replacing.
As far as budget, I don't want to have more than the value of the speakers. Probably somewhere in the 100-200 range for the pair if possible.
I was also wondering how the variable resistor works?
Thanks, John

Jeff

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Re: Snell EII Crossover
« Reply #3 on: 13 Aug 2016, 11:44 pm »
Based on your reply, and correct me if I'm wrong...  You have no sonic goals.  No desire to ship the XOs for a free evaluation (well...shipping cost).  No magnet to check for magnetic components.  The speaker are not worth more than one to two hundred bucks to you.  Your only motivation to replace the wire was because you noticed some oxidation.

OK, let start with your direct question.  The variable resistor trims the tweet (of course).  This was factory set by actual measurement.  It is likely that the replacement tweet came with a new resistor set differently from the first.  If they had files for the original tweet, they might have been able to match up something from stock.  Hence, no resistor change would have been needed.  I have worked on enough Snells to know that the VR is very magnetic, so it will have to go (IMO).  I merely measure them to the milliohm, and replace them with a paralleled equivalent of Mills MRAs.

There are several variations of Livewire.  I have seen some where the two polarities were distinguished by a Red copper looking enamel, and a Greenish enamel.  While this may not explain your patina, it is also possible that the oxidation is limited to flux exposure.  Litz wire will not oxidize up the length of the wire.  My point being, you "might" need to reterminate, but not replace.  Given your level of regard for this project.

Call it OCD, but I would measure exact values before replacing anything on Snells.  Measurements are not everything, but Snell went to the trouble, and I believe in using what they have left us.

I have some to go on, but less than I prefer for a solid recommendation.  Thus, I'm going to make recommendations on a sliding scale.

Tight Budget
-If its not broke, don't fix it :wink:

You specified "Upgade", but you may have meant "Update" as in Maintenance.
-Replace all electrolytics with fresh electrolytics.
-C1 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-27uf-70vdc-50vac-p-3507
-C3 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-27uf-70vdc-50vac-p-3507
-C4 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-15uf-70vdc-50vac-p-4070
-C5 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-15uf-70vdc-50vac-p-4070
-C7 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-39uf-70vdc-50vac-p-3508
-C8 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-82uf-70vdc-50vac-p-4080

~$100
-C1-C3 http://www.soniccraft.com/product_info.php/mundorf-supreme-56uf-600vdc-p-4206
-C4 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-15uf-70vdc-50vac-p-4070
-C5 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-15uf-70vdc-50vac-p-4070
-C6 http://www.soniccraft.com/product_info.php/gen-sonicap-uf-200vdc-p-423
-C7 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-39uf-70vdc-50vac-p-3508
-C8 http://www.soniccraft.com/product_info.php/mundorf-cap-plain-82uf-70vdc-50vac-p-4080

~$200
-C1-C3 http://www.soniccraft.com/product_info.php/mundorf-supreme-56uf-600vdc-p-4206
-C4/C5 http://www.soniccraft.com/product_info.php/gen-sonicap-30-uf-200vdc-p-463
-C6 http://www.soniccraft.com/product_info.php/gen-sonicap-uf-200vdc-p-423
-C7/C8 http://www.soniccraft.com/product_info.php/gen-sonicap-12-uf-200vdc-p-452

If I owned them
-C1-C3 http://www.soniccraft.com/product_info.php/mundorf-supreme-so-56uf-1000vdc-p-233
-C4/C5 http://www.soniccraft.com/product_info.php/gen-sonicap-30-uf-200vdc-p-463
-C6 http://www.soniccraft.com/product_info.php/gen-sonicap-uf-200vdc-p-423
-C7/C8 http://www.soniccraft.com/product_info.php/gen-sonicap-12-uf-200vdc-p-452
-R1 parallel 2 values to equal actual value 2xhttp://www.soniccraft.com/product_info.php/ohm-mills-mra-12-p-644
-R2 http://www.soniccraft.com/product_info.php/05-ohm-mills-mra-12-p-645
-R3 http://www.soniccraft.com/product_info.php/ohm-mills-mra-12-p-696
-One set of binding post (2 assembles) http://www.soniccraft.com/product_info.php/cardas-ccgr-binding-post-p-1389
-12xhttp://www.soniccraft.com/product_info.php/neotech-solid-upocc-copper-in-teflon-20-awg-red-p-1588
-Solder http://www.soniccraft.com/product_info.php/cardas-solder-qe-24ft-p-521
Shock and awe $513.78 :icon_twisted: